The conventional typewriter and computer keyboard, hereinafter called the conventional QWERTY keyboard, consists in diagrammatic representation of four horizontal rows of alphanumeric keys. The keys on one row are offset with respect to the keys on adjacent rows so that diagonal columns are formed. The name "QWERTY" comes from the letter layout of the left side second row. While certain differences exist for non-English language keyboards, these differences are essentially standardized and will be considered "QWERTY" for this application.
The QWERTY keyboard has long been recognized to have many disadvantages, including the following: the most commonly used letters are on the top row rather than on the home (middle) row, where the fingers normally rest; many of the most frequent stroking actions must be done by the weakest fingers (the little fingers); the left hand executes more strokes, both in terms of number and complexity, than the right hand, even though the majority of users are right-handed; the little finger of the right hand must select from at least 15 keys on the modern computer keyboard (IBM-AT compatible enhanced 101 keyboard), some of which are infrequently used and thus require visual selection even by most touch typists; more complex stroking movements are required by the staggered key arrangement than would be required were the keys arranged in orthogonal rows and columns. Furthermore, large numbers of specialized "function", "control", and editing keys have evolved for use with modern computer software. Such function and control keys are often used in combination with other keys, further increasing the difficulty in comfortably and accurately typing all the keys on a modern computer keyboard.
A major problem with the extensive and combined use of specialized computer keys is the awkward postures required for the arms, wrists, hands, and fingers. In recent years these awkward postures, combined with both static and dynamic exertion required to press and hold down keys, have been implicated as causative factors in an epidemic of painful and sometimes disabling occupational injuries. Thus, in addition to the disadvantages of traditional keyboards related to operator performance (speed, accuracy, endurance), these keyboards have also been shown to cause serious health problems. The health problems caused by excessive keyboard use are collectively called repetitive strain injuries. In combination with simple repetition of forceful motion, major factors which are believed to lead to health problems include pronation of the wrist, extension of the wrist, and ulnar deviation, among others. These injurious factors are caused or exaggerated by the use of traditional QWERTY keyboards.
Many prior art keyboard arrangements have been proposed to eliminate the inadequacies of the QWERTY keyboard. These prior art keyboard arrangements generally fall into three groups, referred to herein as the "letter layout alternatives" group, the "geometric alternatives" group and the "chordic alternatives" group. However, as discussed in more detail below, these prior art keyboard arrangements have suffered from incomplete solutions and/or excessive training requirements, and have failed to combine relief from physically stressful postures and motions with productivity equal or exceeding the traditional keyboard and minimal training/retraining requirements. As a result, none of the prior art keyboard arrangements have gained widespread acceptance.
The letter layout alternatives group consists of keyboards in which the standard alphanumeric key set is employed, but the order of the keys has been varied while retaining the standard keyboard geometry. An example of a keyboard that falls into this group is provided in U.S. Pat. No. 2,040,248, issued to Dvorak on May 12, 1936. The Dvorak patent describes a keyboard in which the layout of the alphanumeric keys is based on incidence of usage. Dvorak attempted to position the most heavily used keys (e.g.,"E") in the home row, and to minimize awkward letter combinations and long reaches. However, the keyboard of the Dvorak patent, as well as other keyboards falling into the letter layout alternatives group, suffers from the disadvantage that significant relearning is required before it can be used by a skilled touch typist accustomed to a QWERTY keyboard. Furthermore, this layout does nothing to address the awkward postures and excessive force used by operators of keyboards with traditional key positioning and geometry.
The geometric alternatives group consists of keyboards in which both the standard alphanumeric key set and key layout are typically employed, but the geometry of the keyboard has been varied. As an example, U.S. Pat. No. 1,652,464, issued Dec. 13, 1927 to Tyberg, describes a planar QWERTY keyboard which is split into right and left hand segments. The right and left hand segments are separated from one another and linked in a fixed position to a central segment containing keys such as "release", "shift", "paper", "feed", "return" and "space". As another example, U.S. Pat. No. 4,244,659, issued Jan. 13, 1981, to Malt describes a keyboard employing concave wells for right and left hand segments. The right and left hand segments of the keyboard described by Tyberg and Malt maintain the layout of the QWERTY keyboard so that significant relearning of the keyboard is not required.
However, the keyboards described by Tyberg and Malt, as well as others falling into the geometric alternatives group, do not address the problems of extensive work and excessive key selection that is required by modern keyboards having function and auxiliary keys. Therefore, although providing a keyboard that reduces pronation of the wrist and ulnar deviation, prior art keyboards falling into the geometric alternatives group are not acceptable for use with modern keyboards having multiple function and auxiliary keys.
The chordic alternatives group consists of keyboards in which the alphanumeric key set and the key layout, as well as the keyboard geometry have been varied. Key combinations or "chords" are used to enter letters or numbers which are not represented by single keys. An example of keyboards falling into this group is U.S. Pat. No. 4,897,649, issued to Stucki on Jan. 30, 1990. The Stucki patent describes a keyboard in which multiple sets of two or more keys are mounted on a common base and arranged such as to be comprehended and operated by a single finger. The base is configured to provide separate areas for the right and left hands and a rest for the heels of the hands. The keyboard described by the Stucki patent is typical of keyboards falling into the chordic alternatives group which suffer from the same relearning disadvantages as keyboards falling into the alternative layout group. Furthermore, this class of keyboard requires an increased number of strokes per word, and thus productivity is inherently reduced.
Accordingly, there remains a need in the art for a keyboard that minimizes the strain and effort associated with undesirable postures and motions of the hands, wrists, and arms in typing the alphanumeric keys. Further, it is desirable to provide such a keyboard that simultaneously reduces typing inaccuracies and maintains or increases typing speed while minimizing the need for relearning. Still further, it is desirable to provide a keyboard that minimizes strain and effort of use resulting from the increased usage of specialized function keys and/or auxiliary keys on modern keyboards.